I've had my MacBook for about two months now, and this is the first time something like this has happened. I now have a dark, thin line, about .5 cm long and less than 1mm thick on the upper left corner of my screen (it's right below the "Edit" in the Menu on Safari. I know this wasn't there before, because I would have noticed it. Is there an application I can run, or anything I can do to get rid of the line? Should I send it back to Apple?